1. Field of the Invention
The present invention relates to the surface maintenance and treatment industries in general and, in particular, and methods for cleaning lines on a playing surface.
2. Description of the Related Art
A tennis court is a flat surface defined by multiple boundary lines, namely, sidelines, baselines, service lines, and center lines. The double's sidelines, single's sidelines and baselines define the back courts. The single's sidelines and service lines define the service courts. The center lines divide the service courts. For a hard court, the above-mentioned boundary lines are typically drawn beforehand on a sheet of plastic pasted over a concrete base. For a clay or lawn court, the above-mentioned boundary lines are typically prepared by fixing white tape on a playing surface via tacks.
In general, a clay-surface tennis court or clay court requires daily maintenance in the form of smoothing and watering. The smoothing process is typically performed by dragging a broom or brush across the entire surface of the clay court for smoothing out the loose material on the surface of the clay court. After the smoothing process, the boundary lines on the clay court are usually covered with clay dust. As such, the boundary lines must be cleared of the clay dust before watering and/or before any serious play can be conducted on the clay court. Also, after several games have been played on the clay court, the boundary lines may again be covered by clay dust that necessitates cleaning. Commonly, the cleaning is performed by a person walking a roller brush over all the lines of the clay court, which is very laborious and time-consuming, not to mention tiresome. An example of such a roller brush can be seen in U.S. Pat. No. 4,958,400 by Sugita titled “Line Cleaning Apparatus.”
In nonprovisional patent application U.S. Ser. No. 10/226,978, an apparatus is disclosed which cleans boundary lines on a tennis court automatically, under computer program control. Among the requirements for such an apparatus is the ability for precise navigation and accurate measurement of distance traveled by the apparatus. It is therefore desirable to provide methods for increasing the reliability with which the apparatus measures distance traveled while cleaning boundary lines on a playing surface such as a tennis court.